Dry root rot of chillies, caused by Sclerotium rolfsii,
is a major disease in chilli-growing areas of Andhra Pradesh,
and causes severe losses. The pathogen survives as sclerotia
in soil for a long duration which served as a source of primary
inoculum (Shoeraj Singh et al, 2007). Due to prolonged,
saprophytic survivability of the pathogen, chemical
management is not very effective and is, therefore,
uneconomical. Plant derivatives endowed with pesticidal
properties are being evolved worldwide as alternatives or
supplements to existing chemical pesticides for several
reasons, viz., spiralling costs, environmental hazards and
development of resistance by pathogens and insects (Mishra,
2005). Plant extracts are known to possess antimicrobial
properties and several research workers have studied
antifungal activity of various plant extracts (Seshakiran et
al, 2006; Sheoraj Singh et al, 2007; Deepak Kumar et al,
2008). These reports prompted the present investigation on
in vitro screening of plant extracts, viz., neem (Azadirachta
indica), bottlebrush (Callistemon lanceolatus De),
periwinkle (Vinca rosea), ashoka (Polyalthia longifolia),
curry leaf (Murraya koenigii), prosopis (Prosopis
julifera), onion bulb (Allium cepa) and ginger stem
(Zingiber officinalis) to assess their inhibitory effect on
pathogen mycelial growth, sclerotial production and sclerotial
germination.

Plant extracts: Leaves of neem, Callistemon, Vinca,
ashoka, curry plant and Prosopis plants and onion bulb and
ginger stem were washed with sterilized distilled water and

Short communication

Effect of various plant extracts on dry root rot of chillies caused by Sclerotium rolfsii

G. Bindu Madhavi, S.L. Bhattiprolu and V. Bali Reddy
Regional Agricultural Research Station, Lam

Guntur - 522 034, India
E-mail : gopireddy_bindu@yahoo.co.in

ABSTRACT

Eight different plant extracts were evaluated in vitro against Sclerotium rolfsii causing dry root rot in chillies.
Among these, leaf extract of neem (Azadirachta indica) caused maximum inhibition of mycelial growth (80.74%),
followed by periwinkle Vinca rosea (78.8%) and bottlebrush (Callistemon, 74.8%) respectively. Sclerotial production
was inhibited to an extent of 11% and the inhibition caused was maximum with neem extract, followed by Polyalthia
longifolia and V. rosea extracts. Though sclerotial germination was inhibited by 30% to 95% in various treatments,
the most effective treatment was that of neem leaf extract (95%), followed by ginger extract (92%).

Key words: Sclerotium rolfsii, plant extracts, mycelial growth, sclerotial production

air-dried. A hundred grams of freshly-chopped leaves, bulb
and stem were taken and boiled at 80oC for 10 min. in water.
The material was homogenized for five min., filtered through
muslin cloth and the filtrate was centrifuged at 5000rpm for
15 min. The clear supernatant was collected and used as
100% standard extract. For evaluation of antifungal activity
of these extracts, 10% concentration was made by adding
10ml of standard, basic stock of plant extract to 90ml Potato
Dextrose Agar (PDA) in Petri plates, replicated thrice for
each treatment. PDA without the plant extract served as
the Check. Each plate was inoculated with a sclerotium
taken from 15-day old culture of S. rolfsii. Inoculated plates
were incubated at 25+1oC and data on (i) mycelial growth
and (ii) sclerotial formation were recorded. Sclerotial
germination was recorded by collecting sclerotia from 15-
day old cultures of the pathogen grown on PDA medium.
The sclerotia were at first surface-sterilized with sodium
hypochlorite solution (0.35% available chlorine) and then
washed in sterile distilled water and placed in sterilized Petri
plates under dry conditions. Three sclerotia were suspended
in aqueous extracts obtained from the above plant material
in the cavities of cavity slides placed over a V- shaped glass
rod in a humidity chamber made in sterile Petri plates. The
plates were incubated at 28+1oC for 72 hours. A check was
also maintained with sterilized distilled water in place of
aqueous extract. Each treatment was replicated thrice,
germination of sclerotia was recorded and per cent inhibition
calculated.

J. Hortl. Sci.
Vol. 6(2):156-158, 2011

Prinect Color Editor
Page is color controlled with Prinect Color Editor 4.0.70
Copyright 2008 Heidelberger Druckmaschinen AG
http://www.heidelberg.com

You can view actual document colors and color spaces, with the free Color Editor (Viewer), a Plug-In from the Prinect PDF Toolbox. Please request a PDF Toolbox CD from your local Heidelberg office in order to install it on your computer.

Applied Color Management Settings:
Output Intent (Press Profile): GrayCoated_hdm.icc

RGB Image:
Profile: eciRGB.icc
Rendering Intent: Perceptual
Black Point Compensation: no

RGB Graphic:
Profile: eciRGB.icc
Rendering Intent: Perceptual
Black Point Compensation: no

CMYK Image:
Profile: ISOcoated_v2_eci.icc
Rendering Intent: Perceptual
Black Point Compensation: no
Preserve Black: no

CMYK Graphic:
Profile: ISOcoated_v2_eci.icc
Rendering Intent: Perceptual
Black Point Compensation: no
Preserve Black: no

Device Independent RGB/Lab Image:
Rendering Intent: Perceptual
Black Point Compensation: no

Device Independent RGB/Lab Graphic:
Rendering Intent: Perceptual
Black Point Compensation: no

Device Independent CMYK/Gray Image:
Rendering Intent: Perceptual
Black Point Compensation: no

Device Independent CMYK/Gray Graphic:
Rendering Intent: Perceptual
Black Point Compensation: no

Turn R=G=B (Tolerance 0.5%) Graphic into Gray: yes

Turn C=M=Y,K=0 (Tolerance 0.1%) Graphic into Gray: no
CMM for overprinting CMYK graphic: no
Gray Image: Apply CMYK Profile: no
Gray Graphic: Apply CMYK Profile: no
Treat Calibrated RGB as Device RGB: no
Treat Calibrated Gray as Device Gray: yes
Remove embedded non-CMYK Profiles: no
Remove embedded CMYK Profiles: yes

Applied Miscellaneous Settings:
Colors to knockout: yes
Gray to knockout: yes
Pure black to overprint: no
Turn Overprint CMYK White to Knockout: yes
Turn Overprinting Device Gray to K: no
CMYK Overprint mode: set to OPM1 if not set
Create "All" from 4x100% CMYK: no
Delete "All" Colors: no
Convert "All" to K: no

157

Effect of plant extracts: All plant extracts were by
and large inhibitory to pathogen mycelial growth and sclerotial
formation. Mycelial growth inhibition ranged from 35.18 to
80.74% (Table1). Significantly, highest inhibition was
recorded in the extract obtained from neem leaves (80.1%).
Next in order were extracts obtained from Periwinkle
(78.8%), Callistemon (74.8%), Ashoka (67.03%), Prosopis
spp (52.59%) and Ginger (48.22%). Curry leaf extract was
least inhibitory, as was the extract of onion bulbs.

The plant extracts did not affect sclerotial formation,
although these delayed sclerotial formation by 20 days.
Maximum reduction (Table1) in sclerotial formation (11%)
was recorded in plates amended with neem leaf extract,
followed by Ashoka (9.83%) and Vinca (6.67%).

Aqueous extract of neem leaves inhibited sclerotial
germination in S. rolfsii by 95%. This was followed by ginger
(92%) and Vinca (88%), whereas foliar extracts of ashoka
and prosopis recorded 70% and 50% inhibition, respectively.
Inhibition of sclerotial germination was low with extracts of
onion bulb (Allium cepa, 45%) and bottlebrush (Callistemon
lanceolatus De, 40%) whereas, it was least with extract
of curry leaf (30%).

These results are in agreement with findings of
Shoeraj Singh et al (2007) who reported that foliar extract
of neem followed by that of ashoka, caused maximum
inhibition of mycelial growth, sclerotial production and
viability of S. rolfsii causing collar rot of lentil. Seshakiran
et al (2006) found mycelial growth and sclerotial formation
to be inhibited by extracts of prosopis, neem and onion bulb,
as also recorded in the present investigation. Sonali and
Gupta (2004) reported that acqueous extracts of mustard
cake and neem cake, neem oil reduced in vitro germination
of sclerotia of S. rolfsii causing seedling blight of apple.
Fungitoxic properties of Prosopsis julifera against various

species of Fusarium, Dreschlera and Alternaria were
reported by Raghavendra et al (2002) and Ganesan (1993),
whereas Datar et al (1999) reported fungicidal properties
of leaf extracts of ashoka (Polyalthia longifolia) against
Macrophomina phaseolina. Sharma and Gupta (1995)
observed decrease in root rot incidence in apple using neem
cake as an organic amendment. Similar report came form
Karthikeyan and Karunanidhi (1996) with work on several
soil-borne pathogens. Singh and Dwivedi (1989) found that
Azadirachta indica, Emblica officinalis, turmeric and
ginger extracts reduced hyphal dry-weight and sclerotial
production in vitro in S. rolfsii. Leaf, flower, stem and root
extracts of Vinca rosea were found to be inhibitory to S.
rolfsii, Fusarium oxysporum and Aspergillus niger (Narain
and Satapathy, 1977).

Findings in the present study are in conformity with
those in the above-stated reports and these can be further
exploited for formulating integrated disease management
(IDM) schedule for dry root rot of chillies.

REFERENCES

Datar, V.V, 1999. Bioefficacy of plant extracts against
Macrophomina phaseolina (Tassi) Gold, the incitant
of charcoal rot of sorghum. J. Mycol. Pl. Path.,
29:251-253

Deepak Kumar Srivastava and Heera Lal Yadav. 2008.
Antifungal activity of some medicinal plants against
Fusarium oxysporum f. sp. lycopersici. Ind.
Phytopath., 61:99-102

Ganesan, T. 1993. Fungitoxic effect of wild plant leaf
extracts. Geobios, 20:264-266

Karthekeyan, A. and Karunanidhi, K.1996. Influence of
organic amendments on the intensity of Fusarium
wilt of banana . Pl. Dis. Res., 11:180-181

Mishra, S.R. 2005. Plant Protection and Pest Management.
Discovery Publishing House, Science, 304 p.

Table 1. Effect of various plant extracts on mycelial growth, sclerotial formation and germination of Sclerotium rolfsii

S.l No. Plant extract used Mycelial Per cent Inhibition (%) Sclerotial Inhibition
growth inhibition of sclerotium germination (% over Control)

(cm) of growth formation (%) after 72 h

1 Neem (Azadirachta indica) 1.73 80.61 11.00 5 95
2 Callistemon (Callistemon lanceolatus) 2.26 74.80 5.83 60 40
3 Periwinkle (Vinca rosea) 1.90 78.80 6.67 12 88
4 Ashoka (Polyalthia longifolia) 2.96 67.03 9.83 30 70
5 Curry leaf (Murraya koenigii) 5.90 34.40 3.16 70 30
6 Prosopis (Prosopis julifera) 4.26 52.59 4.50 50 50
7 Onion (Allium cepa) 5.83 35.18 3.20 55 45
8 Ginger (Zingiber officinale) 4.46 48.22 3.63 8 92
9 Check 8.96 0 99.00 100 0

SEM ± 0.117 0.404 2.041
CD (P= 0.05) 0.350 1.211 6.119

Effect of plant extracts on dry root rot of chilli